Benign multicystic peritoneal mesothelioma occurring in bilateral inguinal canals metachronously: a case report

Our plain-English summary of Benign multicystic peritoneal mesothelioma occurring in bilateral inguinal canals metachronously: a case report, by H. Oshikiri, Y. Ozawa, O. Suzuki, et al (Surgical Case Reports, 2022).

The study

• Authors: H. Oshikiri, Y. Ozawa, O. Suzuki, M. Usuda, G. Miyata
• Journal: Surgical Case Reports
• Published: 2022;8(1):44
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Benign multicystic peritoneal mesothelioma (BMPM) is a benign tumor that usually occurs in middle-aged females. Although several published studies have reported the occurrence of this tumor in the abdominal cavity, few have documented its development in the inguinal region.

Case Presentation: We present a case of a 48-year-old female presenting with a bulge in her left inguinal region. Physical examination revealed a golf ball-sized nodule in the left inguinal region that could not be pushed back into the abdominal cavity. Contrast-enhanced computed tomography showed a multicystic tumor; therefore, the patient was diagnosed with inguinal hernia or hydrocele of the Nuck's canal. We performed surgical resection and hernia repair using the mesh plug method. The resected specimen was 80 mm in length and contained a multicystic tumor. Pathological examination showed that the cyst wall was lined by a single layer of cuboidal to single layer squamous epithelium. Immunohistochemistry revealed positivity for calretinin in the epithelial cells, for which a diagnosis of BMPM was established. The patient returned to our hospital after 5 years with symptoms similar to the previous episode, but this time in the right inguinal region. Imaging studies showed a tumor in the right inguinal region with the same characteristics as the previous one. The patient underwent tumor resection and hernia repair using the same technique. The resected tumor was 45 mm in length and had characteristics similar to the previously resected tumor. The presence of calretinin and D2-40 on immunohistochemistry led to the diagnosis of BMPM. There was no recurrence of BMPM for 33 months after the secondary surgery.

Conclusions: Here we present the first report of metachronous BMPM occurring in bilateral inguinal canals. Although the pathogenesis of BMPM remains unclear, reactive changes have been suggested to cause tumors originating from the groin. The treatment of choice for BMPM is surgical resection. For diagnosis, pathological examination with immunostaining can be useful. The most appropriate postoperative follow-up for inguinal BMPM is controversial, and the accumulation of more inguinal BMPM cases is needed.

© 2022. The Author(s).

In plain English

This was a case report of one patient, a 48-year-old female teacher treated at a hospital in Iwate, Japan. She developed benign multicystic peritoneal mesothelioma (BMPM), a benign tumor, in the groin on both sides at different times. She first came with a bulge in her left inguinal region. It was hard to tell apart from a hernia or a hydrocele of Nuck's canal, so surgeons removed it and repaired the hernia with mesh. The removed tumor was 80 mm long and 35 mm across, and staining for calretinin confirmed BMPM. Five years later she returned with a similar lump on the right side. It was removed the same way. It was 45 mm long and 25 mm across and stained positive for calretinin and D2-40, again confirming BMPM. No tumor recurrence was found for 33 months after the second surgery. The authors called this the first such case in their literature review. They concluded that reactive changes may have contributed to the groin tumors and that surgical resection is the standard treatment. The article does not mention asbestos or any other exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: one 48-year-old female teacher with no notable medical history, referred to the authors' hospital (Department of Digestive Surgery, Iwate Prefectural Central Hospital, Japan); dates of treatment not given
• Main results:
  • First tumor (left groin): found at the end of the hernia sac, removed together with mesh plug hernia repair; the resected tumor was 80 mm in length and 35 mm in diameter
  • Pathology of the first tumor: the cyst wall was lined by a single layer of cuboidal to single layer squamous epithelium; calretinin-positive; diagnosed as BMPM
  • Five years later the patient returned with similar symptoms in the right groin
  • Second tumor (right groin): removed with the same technique; 45 mm in length and 25 mm in diameter
  • The second tumor's epithelial cells were positive for calretinin and D2-40, and it was diagnosed as BMPM
  • No tumor recurrence was found for 33 months after the second surgery
• The authors' conclusion: The authors concluded that this was the first reported case of metachronous BMPM in both inguinal canals, according to their literature review. They concluded that reactive changes may have contributed to the groin tumors, that surgical resection is the standard treatment, and that appropriate follow-up for inguinal BMPM is yet to be established.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Bilateral, Inguinal Canal, Inguinal Hernia, Hydrocele, Surgical Resection, Epithelium, Immunohistochemistry.

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